Block #325,901

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 12/23/2013, 9:50:48 AM · Difficulty 10.1957 · 6,477,153 confirmations

2CC
Cunningham Chain of the Second Kind

A sequence where each prime is double the previous prime minus one.

Block Header
Block Hash
9c9962375433c284cc1ff86ed9aaa6f8dc02e8de16647a5bc61ff77a91097883

Height

#325,901

Difficulty

10.195750

Transactions

9

Size

1.96 KB

Version

2

Bits

0a321cac

Nonce

137,547

Timestamp

12/23/2013, 9:50:48 AM

Confirmations

6,477,153

Merkle Root

d6498d68745193dba45087650cd8543a57a70b38f314fd4dbed4990b88262012
Prime Chain Origin

This is the prime chain origin stored in the block header. It is a composite number (not prime itself) — it equals the first prime in the chain multiplied by a primorial. The origin anchors the entire chain to this specific block.

4.662 × 10⁹²(93-digit number)
46625618471288116496…16723794466002978401
Discovered Prime Numbers
p_k = 2^k × origin + 1

These are the actual prime numbers discovered by this block, computed using the verified Primecoin formula. Each number has been independently confirmed to pass the Fermat primality test. Use the FactorDB links to verify any number independently.

1
origin + 1
4.662 × 10⁹²(93-digit number)
46625618471288116496…16723794466002978401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
9.325 × 10⁹²(93-digit number)
93251236942576232992…33447588932005956801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
1.865 × 10⁹³(94-digit number)
18650247388515246598…66895177864011913601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
3.730 × 10⁹³(94-digit number)
37300494777030493197…33790355728023827201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
7.460 × 10⁹³(94-digit number)
74600989554060986394…67580711456047654401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
1.492 × 10⁹⁴(95-digit number)
14920197910812197278…35161422912095308801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
2.984 × 10⁹⁴(95-digit number)
29840395821624394557…70322845824190617601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
5.968 × 10⁹⁴(95-digit number)
59680791643248789115…40645691648381235201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
1.193 × 10⁹⁵(96-digit number)
11936158328649757823…81291383296762470401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
2.387 × 10⁹⁵(96-digit number)
23872316657299515646…62582766593524940801
Verify on FactorDB ↗Wolfram Alpha ↗

What this block proved

The miner who found this block proved the existence of 10 consecutive prime numbers forming a Cunningham Chain of the Second Kind. The prime chain origin — the large number shown above — anchors the chain and is divisible by a primorial (the product of small primes), cryptographically tying these prime numbers to this specific block.

★★☆☆☆
Rarity
UncommonChain length 10

Roughly 1 in 100 blocks. Solid but expected in a healthy network.

How Primecoin's Proof-of-Work Constructs These Primes

Primecoin stores a value called the prime chain origin in each block. The miner found a large integer such that when divided by a primorial (the product of small primes: 2 × 3 × 5 × 7 × …), the result is the first prime in the chain. The origin is deliberately divisible by this primorial — that divisibility is part of the proof.

Prime Chain Origin = First Prime × Primorial (2·3·5·7·11·…)
Source: Primecoin prime.cpp — CheckPrimeProofOfWork()

This is why the origin has many small prime factors — those factors are the primorial divisor. The chain then extends from the first prime using the 2CC formula:

2CC: p₁ (first prime), p₂ = 2p₁ − 1, p₃ = 2p₂ − 1, …
Circulating Supply:57,668,459 XPM·at block #6,803,053 · updates every 60s
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